Dr. Hofmann: I wouldn’t call it varus alignment. I would call it normal alignment. That’s what these patients have that I’m tweaking a little bit into more anatomic position.

As for the varus knee, we’re really talking about mostly male patients and there is an interesting study, a Ranawat award paper that says constitutional varus happens at 3 degrees or more in 32% of men or 17% of women. That means that there are patients out there that have a significant amount of varus in their proximal tibia.

There are two philosophies of anatomic resection versus classic resection. Everybody knows you want to achieve rectangular resection in flexion and extension, and there are two ways to accomplish that. You can follow the anatomy on the femur a little bit closer and then make a cut parallel to the surface of the tibia, both in flexion and extension. It’s different from the classic which always takes a little bit more bone laterally than medially and you have to externally rotate the femur. So if you follow the patient’s anatomy life becomes a lot simpler. You cannot have this conversation unless you get longstanding films. What I’m trying to do is match the patient’s other normal side. Not trying to put the knee in varus, but placing the implant parallel to the ground and that’s what we’re trying to accomplish.

There are the two choices. If you want to tweak a little bit, that is instead of taking a 90 degree cut where you take a lot of bone laterally and a little tiny wafer medially, you can go parallel to the proximal tibia and solve the problem much better and have much easier soft tissue balance.

The femoral preparation is exactly the same. I like to follow the patient’s slope or go a little less. I use flat tibial trials as a block articulating spacer and I almost never have to do any balancing.

So when final implants are in place and the typical X-ray looks a little bit varus. The X-ray doesn’t look perfect, to your eyes perhaps, but it’s anatomic and it’s parallel to the joint. For the male patient or those 13% of women who have varus alignment of the proximal tibia, the mechanical axis, for me, then goes slightly to the medial compartment, which is anatomic, which is normal. The valgus leg I always cut perpendicular, or if they have an uncorrected valgus deformity, I might even leave them a little bit in valgus. This is the technique that we’ve followed for the last 25 years and the survivorship of the femoral and tibial components is extremely high—98%—in this particular study. So Mark Pagnano basically had it right, I think. You can look at your post-operative alignment and you have 0 degrees, plus or minus 3 degrees, it doesn’t necessarily mean you’re going to have better survival at 15 years.

So I say, make your life easier and consider a little gentlemen’s varus for the varus knee.

Dr. Callaghan: Aaron and I are truly partners in crime a lot of times, but on this one I’m going to take the opposite view. Aaron’s a cowboy and does a really good job of doing things that are offbeat, but I am more of a traditionalist.

I actually grew up doing a varus cut on the tibia. I was in the Army at the time at Walter Reed Army Medical Center. Many of you may remember the PCA [porous-coated anatomic] total knee. It was thought that was really the way that the prosthesis should be put in. Even though I’d trained up in New York because I was in PCA country near Baltimore, I was working on this and seeing how it did. But the problem that we were having when we tried to get the 3 degrees of varus, some of them ended up in about 5 degrees of varus, and I’m pretty sure that Aaron wouldn’t want that.

Instead we do what we call a traditional alignment, where we cut the tibia perpendicular to its shaft. If you look—including Chit Ranawat’s results from a total condylar design—the results are about 92% effective. But the most important thing that this study, and many others have shown is that tibial varus alignment is associated with the loosening of the tibial component in the long-term.

If you’ll look at varus articles in the literature, including our own, you’re talking somewhere around 98% success at 20 years, if not closer to 100%. We get a mechanical axis of neutral, a tibio-femoral alignment at 5-9 degrees of valgus, a joint line parallel to the floor, and a perpendicular cut to the tibia. You have to have proper alignment of all 3 planes. Soft tissue balance at extension first. Flexion gap next. Maintain the joint line. Correct sizing of the femoral component to restore offset, rotational alignment and lateralization, and proper cementing technique. That’s what Chit taught me years ago.

We think it’s really important to get good exposure. Sometimes you have to move your perpendicular alignment guide over the center of the talus, not the center of the two malleoli or you’ll still end up in some varus. We reference the tibial tubercle for rotation. We place the tibial component so that we cover the lateral plateau.

On the femoral side, we’ll actually use 7 degrees usually on the varus knee; less on a valgus knee—just the opposite of what Aaron’s talking to you about. And we also want to make sure in the sagittal plane that we don’t provide any flexion of the component. You have to do that by elevating your intramedullary guide for the femur, otherwise you’ll tend to put that component into flexion.

We don’t do huge medial releases any more to get our extension gap right and then we balance the flexion gap to that extension gap. The flexion gap is most important. You need to use Whiteside’s line or the transepicondylar axis. And we put the femoral component in somewhere as Aaron says in 3-4 degrees of external rotation and parallel to the tibial cut when you have the laminar spreaders in place. When you do that, you want to have taken more resection off the lateral side of the anterior femur to get that aligned.

I can tell you in our studies, we have outliers, but no revisions at those long-term periods of follow-up. So Aaron, I’m also from Texas and at times a cowboy, but in regards to changing from traditional alignment to kinematic alignment and varus cut, why would you want to challenge the great success we’ve had all these years?

Moderator Jacobs: We’ll start with Aaron. I think the most common criticism I hear of this approach—shooting for 3 degrees of varus or anatomic varus—is that while you can shoot for 3, when you shoot for 3, it’s a lot easier to get to 5 or 7 than if you shoot for neutral. We’ve heard data from the last series of talks, that there is a 3.8% risk of failure for each degree of varus malalignment. How do you do that? How do you make sure you have such a tight window so that you don’t go into excessive varus?

Dr. Hofmann: I think the argument that 3 degrees is going to become 5 or 6 degrees is lame because our instruments are accurate enough to keep that window narrow. I spent 10 years doing computer navigation and when I was doing navigation, I really found out that it’s better to be a little closer to the patient’s anatomy so that you don’t have to do any soft tissue balancing. I’m going to cut in 2 degrees and that’s going to get me a little closer.

Moderator Jacobs: So John, any response. Is this a lame argument?

Dr. Callaghan: I don’t think it’s a lame argument at all. If you look at the data, and I showed you some of our outliers, we actually get them in a little bit of varus. We don’t do it intentionally, but we get them in that. And the practical reality is that if you’re going to go for those couple of degrees of varus, there’s a chance that you’re going to end up with more and you know that if you do that, if you look long-term, those tibias are not going to do that well.

Moderator Jacobs: Let me just add something. Everybody talks about the PCA days and there’s not very many people in the room old enough to remember—well, you are John, and I am.

Dr. Hofmann: And I am. The problem was those instruments—not many people know this—those instruments were casted. They were mass producing these instruments and they were the least accurate instruments ever to be used. The tibial block is wobbly. You put the medial pin in the medial tibial cutting block and the block kicks into varus. We have navigation, we have lots of ways to narrow the window as Josh was asking about.

Moderator Jacobs: I’d like to follow up on that with a question for John. It’s not only the issue with the instruments in the PCA days, but in those days I would say the results of the PCAs circa 1980s was suboptimal? The question is to what extent did that have to do with the polyethylene at the time? Did it have to do with the fixation interfaces? My question for you is, with modern fixation interfaces, modern cements, and modern polyethylenes that wear less, is varus malalignment as much of a problem long term?

Dr. Callaghan: I guess I’m even more concerned today, Josh, because the patients I operated on when I started in practice in 1984, probably on average weighed about 170 pounds. Today the average person I operate on is somewhere around 34-35 BMI. I would actually flip that discussion, that even if Aaron’s results from 20 years ago, using that 2 degrees of varus looked great, I would still be concerned that today he’s not dealing with the same type of patients. I think you always have to have slop in the system and room for some error. And I say today, with the type of people we’re operating on, you might need more ability to have some slop in the system and not give somebody an alignment that potentially, at least mechanically on the bone, may be deleterious.

Moderator Jacobs: Any response Aaron?

Dr. Hofmann: Yes, I have one last comment. And that is, ask yourself why the medial side of the tibia is bigger than the lateral side? Is that because that patient is walking around with center of hips, center of knees, center of ankles, the medial side is bigger because it carries more weight. And so your argument about a heavy patient having a little bit of varus…probably is a good thing.

Moderator Jacobs: I want to give each of you a chance for a closing statement, start with John.

Dr. Callaghan: First of all I would agree with Aaron that I bet patients like that alignment better short-term. They would rather not have their knee kicked out. They would rather have it where it was their whole life. But I’m concerned long-term that that is not the solution.

Dr. Hofmann: I just want to say I’m talking about the male patient that has varus alignment. I’m not talking about the the right thing to do for a valgus leg or someone that has that kind of anatomy. I’m talking about the anatomic outlier, if you would. Your life will be easier if you kind of tweak a little bit of varus.

Moderator Jacobs: Thanks very much.

Senior Editor: Jay D. Mabrey, M.D., whose 35 year career in orthopedics included residency at Duke University Medical Center, service in the United States Army Medical Corps, Fellowship at the Hospital for Special Surgery and a long, distinguished career at Baylor University Medical Center where, in addition to his overall leadership at that institution, developed the Joint Wellness Program that helped patients get up after surgery more quickly, developed the first virtual reality surgical simulator for knee arthroscopy and chaired the FDA Orthopaedic Device Panel, is Orthopedics This Week’s newest contributing writer and editor.

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Measured Resection Trumps Gap Balancing in TKA

OTW Staff • Thu, August 20th, 2015

This week’s Orthopaedic Crossfire® debate was part of the 16th Annual Current Concepts in Joint Replacement® (CCJR) – Spring meeting, which took place in Las Vegas this past May. This week’s topic is “Measured Resection Trumps Gap Balancing in TKA.” For the proposition is Aaron A. Hofmann, M.D. from the Hofmann Arthritis Institute in Salt Lake City. Bryan D. Springer, M.D. with OrthoCarolina Hip & Knee Center in Charlotte is in opposition. Moderating is Steven J. MacDonald, M.D., F.R.C.S.(C) from the University of Western Ontario.

Dr. Hofmann: I’m going to be talking about measured resection being the simple way to do knee replacement. It’s the way I’ve done knee replacement for the last 30 years and I think it’s the least complicated way to do that, so let me just take you through how that’s done and the reasoning behind it.

There are lots of different names for this measured resection technique, the new name is kinematic, perhaps. That takes it to the extreme. Or the anatomic alignment, basically trying to get your knee balanced. A classic resection basically puts the tibia perpendicular to the long axis and then you spend the rest of the operation trying to balance around that. That’s my bias. Or you can take an anatomic philosophy and go parallel to the tibia and few degrees of varus and make your rectangular resection in extension and flexion. I think we all agree that’s our goal—to have a rectangular resection, in flexion, extension—and I do it by following the patient’s anatomy.

The difference, I think, with gap balancing, perhaps, and measured resection really comes from the tibial side. So if you make a perpendicular cut, you’re going to remove bone lateral and medial and that really means that you’re going to have to spend a lot more time balancing. If you take that same knee and cut parallel with two or three degrees of varus on the tibia, you’re balancing act is almost nothing.

Let me take you through a typical case. A medial sleeve is prepared…we have a mantra for this…medial meniscus, medial sleeve, medial osteophytes and we remove that soft tissue, but basically this is the only releasing we’re doing on a varus knee…just releasing that medial sleeve.

OTW Staff • Sat, July 23rd, 2016

This week’s Orthopaedic Crossfire® debate was part of the 32nd Annual Current Concepts in Joint Replacement® (CCJR), Winter meeting, which took place in Orlando this past December. This week’s topic is “UKA: The Gold Standard for Medial Compartment Disease.” For the proposition is Emmanuel Thienpont, M.D., University Hospital Saint Luc, Brussels, Belgium. Opposing is Chitranjan S. Ranawat, M.D., Hospital for Special Surgery, New York, New York. Moderating is Aaron A. Hofmann, M.D., Hofmann Arthritis Institute, Salt Lake City, Utah.

Dr. Thienpont: I was indeed asked to defend the position for medial OA [osteoarthritis] for which the best treatment is unicompartmental knee arthroplasty (UKA) and not total knee arthroplasty (TKA). When you look at it, it’s always a discussion about if the glass half full or is it half empty. Should we consider UKA for this type of arthritis? When we look at a treatment, it should first be safe, of course. Then it should be effective for your patients—they want to have all their function restored and go back to sports. And then if you have to revise them, it has to be a minimal operation; it has to be as simple as possible.

We asked 300 surgeons what they would want for their own knee if they had medial OA and 87% want the uni. However, only 78% would propose it to their patients. So there is a 9% mis-match. And I hear Chit thinking, ‘But give me the data.’ And he’s right.

So if you look at survivorship, it’s clear that UKA is doing not so good when compared to TKA. There is a 3.5 times higher revision rate. But if you look at the reasons for revision (dislocation/instability, malalignment), these are technical aspects that are surgeon based. Also there is a high rate of unexplained pain, which is also an indication we can address ourselves. So there is a lot of surgeon bias in the reasons to revise a uni.

So why consider UKA then? UKA preserves natural kinematics. That is important. It allows a more physiologic gait pattern. There are less complications in UKA and especially stiffness.

Is a Dash of Varus/Valgus Acceptable? Pagnano v. Whiteside

Elizabeth Hofheinz, M.P.H., M.Ed. • Thu, April 24th, 2014

“It’s time to end the tyranny of the tibia, ” argues Mark Pagnano. “Let’s consider the femur as the prime driver of function.” “Wait, ” says Leo Whiteside. “I suggest that you get ligament balancing and alignment—both in flexion and extension—and don’t settle for anything less.”

This week’s Orthopaedic Crossfire® debate is “Thou Shalt Not Commit Varus or Valgus: Challenging This Dictum.” For the proposition is Mark W. Pagnano, M.D. from Mayo Clinic in Rochester, Minnesota; against the proposition is Leo A. Whiteside, M.D. from The Missouri Bone and Joint Center in St. Louis. Moderating is Cecil H. Rorabeck, M.D., F. R. C. S.(C) from the University of Western Ontario.

Dr. Pagnano: “It’s time to end ‘the tyranny of the tibia.’ Historically in TKA [total knee arthroplasty] our main focus has been on the durability of the construct. That was appropriate because the early designs had some problems. Most of our surgeries 30 years ago were for marked deformities in older patients with low demands or for RA [rheumatoid arthritis]. Now we tend to deal with smaller deformities and shorter hospital stays; the overall risks associated with TKA are substantially different than 20-30 years ago.”

“Moving forward I think that we should devote more attention to the function part of TKA and maybe a bit less to durability. There’s been lots of interest in the last five years in identifying the ‘satisfaction gap’ between TKA and THA [total hip arthroplasty], recognizing that a subset of TKA patients are not satisfied. Surgeons have many thoughts on how to improve function after TKA…with computers, ligament tensioning devices, new implant designs.”

“The typical tibia is in slight varus, but there is substantial variability from some degree of valgus to marked degrees of varus. The typical femur is in 5-10 degrees of valgus, but that is variable.”

“When we go to a total knee replacement we tend to take a monolithic approach. We cut the tibia perpendicular to its long axis and we cut the femur perpendicular to the mechanical axis. This often results in a 5 to 6 degree valgus angle, but that varies.

Whiteside, Dunbar: Six Rounds Over Neutral Alignment

Elizabeth Hofheinz, M.P.H., M.Ed. • Fri, August 16th, 2013

Leo Whiteside says, “Neutral mechanical alignment is the way to go.” Dunbar counters, “But in the future, a patient specific approach to knee implantation strategy is the future of TKA [total knee arthroplasty].”

This week’s Orthopaedic Crossfire® debate is “Straight and Balanced: Gimme That Old Time Religion.” For the proposition is Leo Whiteside, M.D. of the Missouri Bone and Joint Center in St. Louis; against the proposition is Michael J. Dunbar, M.D., F.R.C.S.(C), Ph.D. from Dalhousie University in Halifax, Nova Scotia. Moderating is Daniel J. Berry, M.D. from Mayo Clinic in Minnesota.

Dr. Whiteside: “The knee is so complex that nobody really understands it…just like the universe. Religion is often used to describe how it works, and people’s opinions on total knee replacement begin to sound like religion.”

“I speak to God a lot, sometimes loudly in the OR. The road to salvation is straight and narrow and you get there one step at a time. Excellence is expected…but not perfection.”

“This is how a good knee should work: as the hip and knee flex, the tibia stays in the AP axis and it rotates around the epicondylar axis. As you flex the knee you can see up the tibia, down through the AP axis of the femur and right to the femoral head. A good knee is a little looser laterally than medially in extension; in flexion it’s a bit looser than in extension and looser laterally than medially.”

"The way to do this is bone landmarks aligned separately in flexion and extension with tight ligaments released based on function. Then you cut by the pre-valgus angle of the femur, perpendicular to tibia. The AP axis of the femur is your alignment landmark on the femur, on the bone, in the knee. Stay on the bone and out of trouble. For matched resection, resect the thickness of the implant from the intact surface and that gives you a knee that is balanced in flexion and extension."

“Let’s look at a varus knee. You find a reliable landmark such as the AP axis. Down the center of the canal we make a hole with the reamer and ream down the cement center of the tibia as well.

This week’s Orthopaedic Crossfire® debate is “The Posterior Stabilized Knee: No Post Required.” For the proposition is Aaron A. Hofmann, M.D. from the Hofmann Arthritis Institute in Salt Lake City; against the proposition is Chitranjan S. Ranawat, M.D. from Hospital for Special Surgery. Moderating is John J. Callaghan, M.D. from the University of Iowa.

Dr. Hofmann: “I don’t think you need a post if you have a deficient knee. If you want to save the posterior cruciate ligament (PCL) you must protect it from the saw, so I put a 1/4 inch osteotome in front of it. The problem is really the quality of the tissue you’re saving. In 1987 John Insall told us that the exact tensioning of the PCL is difficult and may depend on luck. I think I’ve begun to believe him over the years, and now I sacrifice the PCL every time.”

“When I went back and looked at my own PCL sparing (I thought) knees about eight years ago, I found that 3% of them had some posterior sag…and that they actually didn’t have a PCL. And the solution that Dr. Ranawat’s going to defend today is the posted version that came about in 1978. The named attributes of this version were improved operative exposure, ease of balancing collaterals, reduction of poly wear, greater contact area, and lower normal forces.”

“But it wasn’t all positive. We know that there are always a small number of patients with stress fractures. And there are some with dislocation (especially with the earlier designs), sometimes requiring reduction with an anesthetic.”

“Then there is the patella clunk syndrome. The fibrous tissue nodule that goes into the intercondylar notch gets stuck and clunks and catches. It’s a small incidence now, but I do occasionally see people with this issue.”

“Each week I have patients complaining about the rattle in their knees.